WILL MY UNITS TAKE THE WEIGHT OF GRANITE OR QUARTZ WORKTOPS?

Ever since the sad demise of MFI, the Manky Furniture Institute, it has been rare to find kitchen units that are too weak for solid stone kitchen worktops. Back when we started, 15 years and more ago, we quite often came across units whose internal supports did not line up with the plastic feet, or where all the strength was in the front of the unit with inadequate support at the back.

Thankfully, this has all changed. By and large, kitchen units are now far stronger than they were. Solid stone – even 30mm thick, super-dense Nero Assoluto granite – will not break your units.
But we have seen increasing numbers of issues to do with support of the stone. The units are strong enough – but they are not supportive enough – they do not offer enough points/lines of contact. This is down to several factors:

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The trend to bigger islands and long runs

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The larger the stone slab on your units, the more potential there is for stresses and failure if not well supported. To put it another way, big pieces of stone require first class unit levelling and support to avoid critical stresses.

The trend to thinner worktops – especially on contemporary style units

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Slab doors – the handleless look – have become increasingly common over recent years. Traditional worktops at 30 or 40mm thickness look a bit heavy on these units. Many people want to “mirror” the door thickness in the worktop thickness. Modern-style quartz designs (not much pattern, or the sparkle/mirror look) suit high gloss kitchens, and quartz is pretty strong so can be fitted thinner than granite. As a result, we find ourselves fitting increasing numbers of 20mm thick worktops. These are mainly in quartz, though occasionally in granite.

The trend to larger hobs

Hobs are getting bigger. Not only has the five-burner hob all but taken over from the traditional four-burner as standard, but we are already seeing more and more customers installing six-burner units, or hobs with built in extractors, like the Bora shown here, courtesy of our friends at HKS, Haywards Heath.

Modern units with reduced worktop support

Some changes to kitchen unit styles are affecting worktops support too. Larger pan drawers create longer sections with weak or no support. And “true handleless” door systems need to have a cutaway in the unit to create finger space to get to the top of the door. This is often achieved with an aluminium trim, which looks great, but has zero real supportive function.
Add in a corner unit, where support tends to be lacking anyway, and you can have a recipe for disaster.

Units in our own showroom. We were changing the worktop over this week and I had the chance to photograph the unit underneath. You can see that support at the front has been reduced to a flimsy aluminium J-section. Lack of support at the back is exacerbated by the fact that our units have to stand well-clear of the wall, because of ducting going along the back.

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Where we have a corner unit, the problem is a hundred times worse. Without battens on the wall and some support at the top of the units, our worktop would be simply hanging in space at the corner, creating huge stresses.

Problems are there for solving...

Problems are there for solving, though. Units are strong, and quartz worktops really are a practical option. The solution is simply one of adding support to make up for what is missing.
We (and other granite and quartz worktop firms) do not in general see ourselves as responsible for the provision of adequate support for your worktops. This is down to the customer and kitchen fitter. But we are flagging up the trends so that together we can ensure that installing your granite or quartz worktops is doable and durable.

Here are pictures and a letter to a recent customer regarding this issue. It’s just to illustrate the kind of problem solving that is involved in fitting granite and quartz worktops where there are support issues.

Dear Helen
Following on from the visit today to template, I have some concerns over the support that is built in to your kitchen with the Magnet cabinet system you have.
The problem stems from the fact that Black Pearl Granite worktops are naturally very heavy, and are not strong when twisted.  The two problems this causes are at the joins and at the hob.

At the hob you will only have about 5cm of stone at the front and rear.  This has no inherent flexural strength and relies on support from underneath.  The aluminium fittings you have can flex quite easily, and will mean the stone will crack at the front or rear of the hob.  Because the hob is over two appliances (which must be removable) we cannot take any support from below.  This really needs to be engineered to be completely rigid, I would recommend 18mm plywood is let in, and cut out for the hob.  Ideally an end panel should be put in between the appliances as we should have support every 600mm if at all possible.

At joins in granite or quartz worktops, we have learned from experience that the springy angle clips flex,  and can cause the joins to break down more quickly than would otherwise be the case.   We strongly recommend that you replace these clips with timber where there are joins.
I would also prefer if you can batten the walls to support the back of the stone worktop around the joins.
I attach annotated drawings to show what I have in mind.

If you decide that this is not possible to do then we would be unable to provide our normal warranty the installation.
As discussed onsite we will not be charging for the aborted template visit as no one could have anticipated this problem.
Once you have a plan for how to move forwards, we can arrange the next steps.  If you feel the solution is to use some other material and forego granite worktops, I will be happy to waive all administration charges and refund your deposit in full.
Kind regards
Andy Phillips (Manager)

We are Affordable Granite, the leading installer of granite and quartz worktops in Surrey, Sussex and across the South East. For samplesquotes and any questions connected with any aspect of worktop installation or kitchen design, please don’t hesitate to contact us on 01293 863992 or by email on sales@affordablegranite.co.uk/ .

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